Joining Flat Belt

[Jim]

G'day all, I have some PMR flat belt and have been joining it using superglue but the join isn't so smooth when it goes over pulleys.

I've tried to overlap it just enough to hold, but it still feels stiff when it turns over and there's a distinct bump.

Any hints anyone can give me?

[classixs]

Can´t those flat belts be glued straight on end to end, if cut perfectly straight, like when making any other o-ring?

Would reduce the stiff point to being almost gone.

[Jim]

Can´t those flat belts be glued straight on end to end, if cut perfectly straight, like when making any other o-ring?

Would reduce the stiff point to being almost gone.

I've only ever tried what PMR suggest with the slight overlap.
https://www.pmmodelengines.com/shop/machine-tools/line-shaft/belting/

[Nick]

Can you sand the ends at an angle on a belt sander so when they overlap it makes the same thickness as the belt? (Left of pic)

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[classixs]

If they´re appear to be made of a similar material as o-rings, and you have a few millimeters of excess belt to sacrifice, i´d suggest that you try and glue them straight onto each other, to give them a good yank and see if it´ll hold up.
A homemade o-ring is surprisingly strong at the connection point 

[classixs]

Would be easy to take the thickness down, main problem is that cyanoacrylate doesn´t stretch at all once hardened, and the stiffness issue will remain the same.
Would remove the visual bump though 

[Nick]

Didn’t think of that... maybe he should try your end to end method but at an angle like on the right of the pic?

[ShadetreeMotorcycle]

Can you sand the ends at an angle on a belt sander so when they overlap it makes the same thickness as the belt? (Left of pic)

(Attachment Link)

I have used the far left joint on PMR belt, sanding the angle so that I had at least a 1/4" overlap. I also took some care to not slide the top to far over the bottom so as not to create a "thick" spot.
  Next I spread the CA glue quite thin but used Medium viscosity, not the thin runny stuff. I weighted it with wax paper between Weight and belt to ensure not to stick my weight to the belt.
  Next I let it dry completely, then inspect...the super glue drys hard and stiff, I carefully take the joint an "massage" it in my fingers to slightly break down the stiff spot...sort of cracking the slab of glue so it's not one flat chunk but not stress it so much as to degrade the bond, I like to think of the glue as a plate of glass laminated between the rubber belt layers you want to break into small pieces like a puzzle but not break the bond between the top and bottom, the smaller pieces go around a pulley much smoother than a slab.
  Lastly, dispite best efforts it often will come out the joint is a slight thick spot in the belt, I roll it inside out and sand the joint area back so it's not thick, or even .003 thinner than the rest of the belt...all this fussing with the joint area will greatly soften it.
  The next time I make one I am going to try "flexible" super glue! I found it at a premium hobby shop but it is also used in the Archery industry to glue feathers on to arrow shafts. It does not truly dry soft as rubber but you can feel it's much softer the hard Regular CA glue. It does cost a bit more than Regular CA glue but may be worth the benifits.
  Hope this helps!2

[ShadetreeMotorcycle]

Also forgot to mention... When I am sanding in the taper for the overlap joint, it is VERY tempting to stop to soon as the thin end will still look crisp and Clean, don't stop there I keep sanding until the tip is so thin it looks kind of frayed like the edge of a small song bird feather...I can not get to this level of thinness on my belt sander as the belt is to course, I use small self made sanding blocks and experiment with grit till I get what I like. You would think the "frayed" end would look ugly but I wash the belt dust off with rubbing alcohol before glueing and when it's all done it looks pretty nice. It's not a 30 second job with sanding blocks but I think it's worth the extra effort. Hope this helps!

[Jim]

Cheers for all the thoughts and suggestions, appreciated!

[Steam Technology]

Stitch it or use belt lacing joiners.

[Nick]

Stitch it or use belt lacing joiners.

I did the “angled method” and stitched this belt on the sewing machine. I’ll see if I can remember where I put the belt and get a picture...

[Jim]

I've got some leather I saved from a few leather lounges that were getting thrown out. Thinking of using some leather and stitching it.

Thanks for the vid Nick nice seeing the Maxitrak Case again.